The Company’s

available-for-sale

investment securities are carried at fair value with unrealized net gains or losses reported within accumulated other comprehensive income (loss) in shareholders’ equity. The Company had no outstanding investment securities classified as

held-to-maturity

at March 31, 2021 and December 31, 2020.

The amortized cost, gross unrealized holding gains and losses, and fair value of

available-for-sale

investment securities were as follows:


	March 31, 2021									December 31, 2020
(Dollars in Millions)	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value		Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
U.S. Treasury and agencies	$	24,401	$	288	$	(372	)	$	24,317	$	21,954	$	462	$	(25	)	$	22,391
Mortgage-backed securities
Residential agency		116,629		1,230		(1,683	)		116,176		98,031		1,950		(13	)		99,968
Commercial agency		6,254		53		(221	)		6,086		5,251		170		(15	)		5,406
Asset-backed securities		197		5		–			202		200		5		–			205
Obligations of state and political subdivisions		8,687		546		(18	)		9,215		8,166		695		–			8,861
Other		7		–		–			7		9		–		–			9
Total available-for-sale	$	156,175	$	2,122	$	(2,294	)	$	156,003	$	133,611	$	3,282	$	(53	)	$	136,840

Investment securities with a fair value of $39.3 billion at March 31, 2021, and $11.0 billion at December 31, 2020, were pledged to secure public, private and trust deposits, repurchase agreements and for other purposes required by contractual obligation or law. Included in these amounts were securities where the Company and certain counterparties have agreements granting the counterparties the right to sell or pledge the securities. Investment securities securing these types of arrangements had a fair value of $596 million at March 31, 2021, and $402 million at December 31, 2020.

The following table provides information about the amount of interest income from taxable and

non-taxable

investment securities:


	Three Months Ended March 31
(Dollars in Millions)	2021		2020
Taxable	$	455	$	640
Non-taxable		62		52
Total interest income from investment securities	$	517	$	692

The following table provides information about the amount of gross gains and losses realized through the sales of

available-for-sale

investment securities:


	Three Months Ended March 31
(Dollars in Millions)	2021		2020
Realized gains	$	25	$	73
Realized losses		–		(23	)
Net realized gains	$	25	$	50
Income tax on net realized gains	$	6	$	13

The Company conducts a regular assessment of its available-for-sale investment securities with unrealized losses to determine whether all or some portion of a security’s unrealized loss is related to credit and an allowance for credit losses is necessary. If the Company intends to sell or it is more likely than not the Company will be required to sell an investment security, the amortized cost of the security is written down to fair value. When evaluating credit losses, the Company considers various factors such as the nature of the investment security, the credit ratings or financial condition of the issuer, the extent of the unrealized loss, expected cash flows of underlying collateral, the existence of any government or agency guarantees, and market conditions. The Company measures the allowance for credit losses using market information where available and discounting the cash flows at the original effective rate of the investment security. The allowance for credit losses is adjusted each period through earnings and can be subsequently recovered. The allowance for credit losses on the Company’s available-for-sale investment securities was immaterial at March 31, 2021 and December 31, 2020.

At March 31, 2021, certain investment securities had a fair value below amortized cost. The following table shows the gross unrealized losses and fair value of the Company’s

available-for-sale

investment securities with unrealized losses, aggregated by investment category and length of time the individual investment securities have been in continuous unrealized loss positions, at March 31, 2021:


	Less Than 12 Months					12 Months or Greater					Total
(Dollars in Millions)	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. Treasury and agencies	$	9,519	$	(372	)	$	–	$	–		$	9,519	$	(372	)
Residential agency mortgage-backed securities		59,916		(1,678	)		150		(5	)		60,066		(1,683	)
Commercial agency mortgage-backed securities		4,130		(221	)		6		–			4,136		(221	)
Asset-backed securities		–		–			2		–			2		–
Obligations of state and political subdivisions		1,037		(18	)		–		–			1,037		(18	)
Total investment securities	$	74,602	$	(2,289	)	$	158	$	(5	)	$	74,760	$	(2,294	)

These unrealized losses primarily relate to changes in interest rates and market spreads subsequent to purchase of the investment securities. U.S. Treasury and agencies securities and agency mortgage-backed securities are issued, guaranteed or otherwise supported by the United States government. The Company’s obligations of state and political subdivisions are generally high grade. Accordingly, the Company does not consider these unrealized losses to be credit-related and an allowance for credit losses is not necessary. In general, the issuers of the investment securities are contractually prohibited from prepayment at less than par, and the Company did not pay significant purchase premiums for these investment securities. At March 31, 2021, the Company had no plans to sell investment securities with unrealized losses, and believes it is more likely than not it would not be required to sell such investment securities before recovery of their amortized cost.

During the three months ended March 31, 2021 and 2020, the Company did not purchase any

available-for-sale

investment securities that had more-than-insignificant credit deterioration.

The following table provides information about the amortized cost, fair value and yield by maturity date of the

available-for-sale

investment securities outstanding at March 31, 2021:


(Dollars in Millions)	Amortized Cost		Fair Value		Weighted- Average Maturity in Years		Weighted- Average Yield (e)
U.S. Treasury and Agencies
Maturing in one year or less	$	4,264	$	4,292		.4		1.54	%
Maturing after one year through five years		11,534		11,694		2.6		1.15
Maturing after five years through ten years		7,364		7,150		8.1		1.33
Maturing after ten years		1,239		1,181		13.0		1.78
Total	$	24,401	$	24,317		4.4		1.31	%
Mortgage-Backed Securities (a)
Maturing in one year or less	$	110	$	112		.6		2.07	%
Maturing after one year through five years		47,936		49,021		3.6		1.40
Maturing after five years through ten years		74,785		73,077		7.8		1.46
Maturing after ten years		52		52		11.9		1.13
Total	$	122,883	$	122,262		6.1		1.44	%
Asset-Backed Securities (a)
Maturing in one year or less	$	–	$	–		.9		2.69	%
Maturing after one year through five years		3		4		2.9		1.74
Maturing after five years through ten years		194		197		6.0		1.08
Maturing after ten years		–		1		13.6		2.41
Total	$	197	$	202		5.9		1.09	%
Obligations of State and Political Subdivisions (b) (c)
Maturing in one year or less	$	178	$	182		.7		4.21	%
Maturing after one year through five years		1,451		1,539		3.5		4.39
Maturing after five years through ten years		6,624		7,066		6.9		3.86
Maturing after ten years		434		428		17.4		2.57
Total	$	8,687	$	9,215		6.7		3.89	%
Other
Maturing in one year or less	$	7	$	7		.1		2.07	%
Maturing after one year through five years		–		–		–		–
Maturing after five years through ten years		–		–		–		–
Maturing after ten years		–		–		–		–
Total	$	7	$	7		.1		2.07	%
Total investment securities (d)	$	156,175	$	156,003		5.9		1.55	%

(a)	Information related to asset and mortgage-backed securities included above is presented based upon weighted-average maturities that take into account anticipated future prepayments.

(b)	Information related to obligations of state and political subdivisions is presented based upon yield to first optional call date if the security is purchased at a premium, and yield to maturity if the security is purchased at par or a discount.

(c)	Maturity calculations for obligations of state and political subdivisions are based on the first optional call date for securities with a fair value above par and the contractual maturity date for securities with a fair value equal to or below par.

(d)	The weighted-average maturity of total available-for-sale investment securities was 3.4 years at December 31, 2020, with a corresponding weighted-average yield of 1.61 percent.

(e)	Weighted-average yields for obligations of state and political subdivisions are presented on a fully-taxable equivalent basis based on a federal income tax rate of 21 percent. Yields on investment securities are computed based on amortized cost balances.